Everything You Need to Know About Checking Your Car’s Tire Pressure
Car experts say that it’s important to check the air pressure in your tires as part of regular maintenance, but they don’t always explain why. We will explain the purpose and reasons why it’s necessary, the difference between air- and nitrogen-inflated tires, and some issues that could arise with improper inflation. You can also follow our step-by-step guide on checking your car’s tire pressure.
Tire Pressure: Why It’s Important
The air pressure in your tires makes a significant difference in the way that the vehicle handles. Having the optimal level of inflation makes driving more comfortable and safer, particularly in inclement weather such as heavy rain, ice or snow. Improper air pressure in poor driving conditions could cause loss of control over the vehicle.
Additionally, proper air pressure leads to better fuel efficiency. Underinflated tires increase fuel consumption by 2 percent per pound of pressure below the optimum level. It also increases rolling resistance, which wears down the tread on the tires faster. The life of tires that are 6 pounds per square inch below the recommended PSI is substantially reduced.
Avoid Maximum PSI
Filling your tires to the maximum level of air pressure also has detrimental effects. The recommended PSI for vehicles is generally between 30 and 35 PSI, indicating the amount of air pressure required to support the maximum load-carrying capacity of the vehicle. The maximum cold pressure for your tires is indicated on the sidewall below the manufacturer name, usually reading “Max. Press. 35 PSI” or something similar. The term “cold pressure” indicates when the tires are cold, such as before driving or after sitting for a few hours.
Inflating your tires to the maximum level changes the handling characteristics because the sidewall doesn’t give as much. This can cause problems with braking and make the rear of the vehicle slide out as you drive around corners. Maximum PSI can also reduce the life of the tires because the rubber rounds at the top during driving, which may lead to blowouts and poor traction.
Finding the Recommended Tire Pressure
Maintaining optimal tire pressure improves fuel economy, safety, vehicle handling, and the life of your tires. You can find the recommended level for your tires on one of the following locations:
- in the console
- in the owner’s manual
- on the doorjamb sticker
- on the fuel door
- on the lid of the trunk
Why Tire Pressure Must Be Checked Regularly
There are several reasons why you need to check the air pressure in your tires on a regular basis and before taking a road trip. Having proper air pressure ensures:
- optimized fuel efficiency and performance
- stabilized tire structure: ideal handling, responsiveness and traction
- avoidance of possible rolling hazards
- improved performance and sturdiness to complement the needs of the vehicle
- prevention of sidewall flexing and tire squirm
- reduced heat buildup
Differences Between Air and Nitrogen
Some drivers prefer to inflate their tires with nitrogen because, according to some sources, it offers a slight advantage over using compressed air. Some of these benefits include:
- better tire-pressure retention
- cooler tire temperatures while driving
- decreased rubber oxidation, which reduces the chance of a tire blowout
- increased fuel efficiency
- prolonged tire life
These benefits are the result of the differences between compressed air and nitrogen. Pure nitrogen is a slow, inactive gas – it doesn’t react with many materials, but the oxygen in air is a fast, active gas that reacts with numerous materials, resulting in oxidation. Nitrogen molecules can’t escape as easily as air through the microscopic spaces between the rubber molecules in tires.
However, there are also disadvantages to inflating vehicle tires with nitrogen rather than air:
- it costs about $5 per tire, while compressed air is free
- it’s not readily available
- routine tire-pressure checks and tire maintenance are still required
- tire maintenance might be a bit more complicated because of it
Although nitrogen-filled tires retain pressure more steadily and don’t require fill-ups as often as air-filled tires, the results between the two are nearly the exact same. Manufacturers design tires to perform with air, so they should run as intended for you as long as you maintain proper tire pressure.
Checking and Adjusting Tire Pressure: A Step-by-Step Guide
Checking the air pressure in your tires is easy if you know the proper steps:
- Purchase an accurate tire pressure gauge, and make sure to always have it in your vehicle, such as in the center console or glove box. Keep a record of the tire pressure in a small notebook that you also leave in your vehicle or on your smartphone. You can use this record to also track fuel efficiency and to tell whether something is wrong with your tires.
- Find the recommended tire pressure for your vehicle, which is located in the owner’s manual, on the sticker in the doorjamb, in the console, on the inside of the trunk lid or on the fuel door. Sometimes different pressures are required for the front and rear tires.
- It’s important to check your tires when they are cold, such as before you drive or a couple hours after driving. This is because the recommended tire pressure is meant for cold tires, and tires become warm as you drive. If you have to drive to get air, it’s best to drive less than 1 mile.
- Remove the valve caps from the tires, and put it in your pocket or to the side where you can’t lose it.
- Press the tire gauge firmly onto the valve stem, during which you may hear a slight hiss. It only takes a second or two for the gauge to read the tire pressure, and you may hear another hiss when you remove the gauge.
- The reading will be in PSI, whether you have a digital gauge or a traditional gauge with a metered stick. Recording the results as you check each tire will help you when you fill them up later.
Adjusting the tire pressure is just as easy when you follow these steps:
- Pull your vehicle as close to the air compressor as possible. Ideally, the hose will reach all four tires. You could also buy a portable air compressor to adjust the tire pressure at home.
- Turn on the compressor, which may require a few coins at some gas stations.
- Remove the valve caps, putting them in your pocket or to the side.
- Press the end of the hose onto the valve stem.
- When you press the lever, you should feel and hear the air flowing into your tires.
- Check the tire pressure as you fill up by reading the gauge built into the hose, and slightly over inflate the tires. Use your tire gauge to get a more accurate reading.
- If the tire pressure is too high, press the gauge onto the valve stem just enough to release some air, during which you will hear a hissing sound.
- Continue checking the pressure, filling the tires or releasing air until the pressure reaches the optimal level. If your tires are warm when you add air, add 3 PSI to the recommended amount.
- Put the valve caps back on and tighten them.
In general, you should check your tire pressure every 30 days when outdoor temperatures remain steady. When temperatures begin to vary, such as when the seasons change, it’s recommended that you check the tire pressure every week or two or every time that you refuel. This is because gases expand and contract when temperatures increase and decrease respectively. Every 10-degree change makes the tire pressure rise and fall by 1 PSI.
Now that you know the importance of tire pressure and how to check and adjust it regularly, you can make your vehicle safer and benefit from better fuel efficiency and a smoother ride.
Do you already check your tire pressure regularly?
How often do you have to adjust it?
Do you prefer nitrogen-inflated or air-inflated tires?